My coworker Heykel Aouani will defend his PhD on September 08th (13:00, Ponte Amphi). The thesis is entitled "Optical nanoantennas to enhance and control molecular fluorescence in subwavelength volumes".
- Prof. Romain Quidant (ICFO Barcelona, reviewer)
- Dr Alexandre Bouhelier (ICB Dijon, reviewer)
- Prof. Xavier Letartre (INL Lyon)
- Prof. Emmanuel Fort (ESPCI Paris)
- Dr. Herve Rigneault (Fresnel Marseille)
- Dr. Jerome Wenger (thesis supervisor)
Abstract: Optical nanoantennas allow manipulation, connement and enhancement of light in subwavelength volumes. The applications of these nano-objects are related to various fields such as nano-light sources, photovoltaic, microscopy, spectroscopy ... The physical properties of these nanoantennas depending mainly on their nature, sizes and geometries, the experimental characterization of these nano-objects is essential because it allows to improve signicantly their design and amplify the electromagnetic responses. The focus of this work concerns the characterization and exploitation properties of optical nanoantennas. Several experimental characterization techniques of nanoantennas have been developed during this thesis : fluorescence correlation spectroscopy FCS, temporal dynamics monitoring of quantum dots, spectroscopy by saturated excitation of fluorescence. These techniques were applied to study different types of optical antennas : dielectric microspheres, bare nanoapertures and corrugated nanoapertures. These optical antennas have been used to effectively improve the detection of fluorescent molecules in solution, with fluorescence enhancement greater than a factor of 100, together with a directivity control of the fluorescence emission, opening new opportunities in biophotonics.
Un séminaire thématique franco-japonais sur la nanophotonique est organisé du 07 au 09 novembre 2011 au Japon (région Ise Kanko, entre Osaka et Tokyo). L'objectif est de permettre une meilleure connaissance des acteurs japonais de la nanophotonique et des technologies correspondantes.
Pour tout renseignement, contactez daniel.bloch[@NOSPAM]univ-paris13.fr
Subwavelength apertures milled in metallic films are receiving a growing interest to tailor light at the nanoscale, and improve the detection methods of single molecules.
In an article published in the July 04th issue of Optics Express, we quantify the influence of the number of circular corrugations surrounding a central nanoaperture to further enhance the fluorescence emission per molecule. This work has three aspects of general interest:
1) We quantify both the excitation and emission gains contributing to the fluorescence enhancement, providing the first complete characterization of corrugated apertures as the number of corrugations is increased.
2) We demonstrate efficient single molecule detection with fluorescence rates clearly above 10,000 counts/second with a simple low NA lens.
3) We show that a single groove milled around a nanoaperture already provides a supplementary 3.5 fold increase in the fluorescence enhancement as compared to a bare nanoaperture. This constitutes the first experimental observation of the effect numerically predicted in Bonod et al, Optics Express 16, 2276-2287 (2008).